This invention relates to medicinal compositions of matter comprising an analgesic in combination with a naturally-occurring chondro-protective agent. The compositions according to the invention are suitable for oral administration. Alternatively, the combinations of the invention may be administered by any conventional means of drug administration.
Osteoarthritis (xe2x80x9cOAxe2x80x9d) is the most common form of joint disease in the United States. It represents a major concern for health care providers because of its marked impact on the quality of life of those afflicted by it.
In healthy conditions, articular cartilage forms a smooth surface between articulating bone ends to reduce the friction caused by movement. This friction is further reduced by the synovial fluid. Articular cartilage consists of chondrocytes and two major macro-molecules; i.e., collagen and proteoglycans, which are synthesized by and deposited around the chondrocytes. The chondrocytes also synthesize the synovial fluid which bathes the articular cartilage.
The structural integrity of the articular cartilage is the foundation of optimal functioning of the skeletal joints in the hip, shoulders, elbows, hocks and stifles. Impaired function of skeletal joints will dramatically reduce mobility such as rising from sitting position or climbing and descending stairs. To maintain the structural integrity and the proper functioning of the articular cartilage, the chondrocytes constantly synthesize collagen and proteoglycans, the major components of the articular cartilage, as well as the friction-reducing synovial fluid. This constant synthesis of the macromolecules and synovial fluid provides the articular cartilage with the repairing mechanism for most of the wearing caused by friction between the bone ends. However, it also leads to the constant demand for the supply of precursors, or building blocks, for the macromolecules and synovial fluid. Lack of this precursors will lead to defects in the structure and function of the skeletal joints. This deficiency occurs often when activity levels are very high, or cartilage tissue has been traumatized.
An adequate supply of metabolic precursors or building blocks is thus paramount to replacement and repair of the constituents of skeletal joints, connective tissue and synovial fluid. Proteoglycans (or mucopolysaccharides) form the ground substance of cartilage, bone and joint fluid. Proteoglycans are comprised of proteins linked to glycosaminoglycans (GAGs). The building block GAG subunit of the proteoglycan in cartilage and bone is chondroitin sulfate. Chondroitin sulfate A is present in cornea and cartilage. Chondroitin sulfate B (G-heparin) is found in tendon, aorta, skin and heart valves. Chondroitin C is found in cartilage, tendon and umbilical cord and similar tissues. The building block GAG subunit of the proteoglycan in joint fluid is hyaluronic acid. Intercellular solutions of hyaluronic acid are viscous and thus assist in lubrication of the joints of body skeleton. Hyaluronic acid is synthesized from the metabolic precursor, glucosamine. The availability of glucosamine in cartilage tissue can be rate-limiting to the enzymatic step leading to the production of proteoglycans. Exogenous glucosamine serves to drive the biosynthetic pathway forward past the rate-limiting blockage point. Glucosamine serves as a substrate for a kinase enzyme which yields glucosamine-6-phosphate, the rate-limiting precursor in proteoglycan synthesis.
One class of materials that are commonly prescribed for the treatment of the symptoms of OA are the non-steroidal, anti-inflammatory drugs (xe2x80x9cNSAIDSxe2x80x9d). Many such compounds are known to those skilled in the art, including without limitation: Naproxen Sodium, Oxaprozin, Diclofenac, Etodolac/Lodine, Feldene, and Naprelan. While NSAIDS can provide symptomatic relief for those afflicted with OA, they are typically known to facilitate or accelerate the progression of OA by unfavorably altering the balance of destruction and repair in joints that are affected with OA. Further, NSAIDS have a known risk of liver toxicity, kidney toxicity, gastritis, ulcers, and gastrointestinal (xe2x80x9cGIxe2x80x9d) bleeding. GI bleeding is believed to be the single largest contributing cause of the 100,000 deaths in the United States each year attributable to medication side effects (J.A.M.A. 4-98).
There is a class of compounds which may be generically referred to as naturally-occurring chondro-protective agents (xe2x80x9cNOCPA""sxe2x80x9d). A wide range of NOCPA""s are known to those skilled in the art, and include, without limitation, such compounds as glucosamine sulfate, chondroitin sulfate, N-acetyl glucosamine, hyaluronic acid and its derivatives such as hyaluronan, and the glycosaminoglycans. Numerous disclosures describe therapy of damaged tissues by introduction of such precursors in the metabolic pathway leading to biosynthesis of the macromolecules of connective tissues. For example, in U.S. Pat. No. 3,697,652 (Rovati et al.), N-acetylglucosamine is used to treat degenerative afflictions of the joints. In U.S. Pat. No. 3,683,076 (Rovati et al.), glucosamine salts are described as pharmaceutically useful for treatment of osteoarthritis and rheumatoid arthritis. U.S. Pat. No. 4,647,453 (Meisner) and U.S. Pat. No. 4,772,591 (Meisner) disclose the use of glucosamine salts for treatment of degenerative inflammatory disease and as a means of accelerating wound healing. In U.S. Pat. No. 4,801,619 (Lindblad), a hyaluronic acid preparation is claimed to be effective for treatment of steroid arthropathy and progressive cartilage degeneration caused by proteoglycan degradation. A combination of glucosamine, chondroitin and manganese is claimed in U.S. Pat. No. 5,364,845 (Henderson) as a means of protecting and repair of connective tissue. While these materials are capable of providing relief of symptoms of OA after about 4 to 6 weeks of administration, they offer no short term or immediate relief of OA symptoms. However, compounds within this broad class appear to have a chondroprotective effect which may favorably alter the progressive course of chronic OA. Generally, the NOCPA""s are very safe and pose no substantial health risk associated with their use.
One common agent used in the rapid, short-term, symptomatic relief of the painful symptoms of osteoarthritis is acetaminophen, including its analogs and therapeutically effective derivatives, as such are known to those skilled in the art of medicinal chemistry. While having been the subject of much study in recent years owing to its widespread use, acetaminophen provides no long term relief to OA, nor does it have significant impact on the progression of OA.
None of these prior investigators, however, disclose a composition comprising an analgesic for short term relief from the symptoms of osteoarthritis in combination with a naturally-occurring chondroprotective agent that functions over the long term, and which thus work synergistically to simultaneously treat both the causality and the symptoms of OA.
The present invention is concerned with medicinal compositions of matter useful in the treatment of osteoarthritis. A composition according to the invention in general comprises an analgesic component and a chondro-protective agent. The analgesic component may comprise any material which is known to have analgesic properties, but preferably comprises a synthetic analgesic selected from the group consisting of: acetaminophen, an acetaminophen derivative, or an acetaminophen analog. In a preferred embodiment, the chondro-protective agent is naturally-occurring, and preferably comprises a glycosaminoglycan. However, other preferred chondro-protective agents may comprise a compound selected from the group consisting of: glucosamine sulfate, chondroitin sulfate, N-acetyl glucosamine, hyaluronic acid and hyaluronan.
According to a the invention, the analgesic component may be present in any amount between 0.05% and 99.5% by weight based upon the total weight of the composition, including every hundredth percentage therebetween. The chondro-protective component may be present in any amount between 0.05% and 99.5% by weight based upon the total weight of the composition, including every hundredth percentage therebetween.
Preparation of a composition according to the invention may be carried out by cocomminutation of the chondro-protective agent with the analgesic component. Alternatively, solutions of each component in water or other suitable solvent in which the selected components are mutually soluble may be provided and admixed with one another, the solvent being subsequently removed to provide an intimate mixture of the components.
The invention further comprises a process for treating osteoarthritis comprising the steps of first providing a composition according to the invention and subsequently introducing the composition into a human body that is afflicted with osteoarthritis. Although principally directed at treating humans, the inventive compositions may also be administered to mammals in general which suffer from osteoarthritis, including horses. It is preferred that the introduction of a composition according to the invention be carried out on at least a daily basis, for a time period sufficient for the benefits of a composition according to the invention to become manifest. It is preferred that the total mass of composition according to the invention to be introduced into a mammalian subject be in the range of between 0.500 grams and 10.00 grams, including every hundredth gram therebetween, per introduction, and each of the chondroprotective component and analgesic components be present in a therapeutically effective therapeutic amount. The introduction of a composition according to the invention may be undertaken orally, transdermally, buccally, intravenously, intramuscularly, parenterally, or sublingually using means known to those skilled in the art.
Analgesics including acetaminophen and its derivatives or analogs provide rapid relief from symptoms of OA which the NOCPA""s cannot. The NOCPA""s provide long-term benefits which acetaminophen or its derivatives and analogs cannot. Each of these types of materials complement each other by different, mutually-compatible mechanisms of action. A great advantage of the invention is that neither of these agents poses a risk of GI bleeding. The use of such novel combination to treat OA in the stead of NSAIDS when possible provides relief of symptoms, favorably alters disease progression, and is capable of preserving the lives of thousands of patients each year by eliminating the possibility of gastrointestinal bleeding.
In one preferred form, the present invention is directed at a therapeutically effective composition of matter which comprises acetaminophen (or one of its derivatives or analogs) and a naturally-occurring chondroprotective agent (xe2x80x9cNOCPAxe2x80x9d) in combination with one another for simultaneous administration by the patient themselves, which is preferably oral administration of the composition in the form of a friable tablet, pill, or capsule. In embodiments, a combination according to the invention may be administered intravenously, intramuscularly, subcutaneously, parenterally, buccally, or sublingually.
The optimum dosage levels are dependent upon the NOCPA and acetaminophen used, the determination of such optimum levels being within the level of skill of one of ordinary skill in the art. In the case of glucosamine sulfate, a single daily dose of 1,500 milligrams per day per 150 pounds of body weight is an effective amount for total relief of symptoms or osteoarthritis after being administered 4 to 6 weeks. In the case of chondroitin sulfate, a dose of 1,200 milligrams per day per 150 pounds of body weight is an effective amount for relief of symptoms after being administered 4 to 6 weeks. The amount of acetaminophen needed for symptomatic relief preferably varies from 1,000 to 2,000 milligrams two to four times daily, depending upon the patient""s individual needs.